Method and cooking apparatus for improved fresh air supply

ABSTRACT

In a method for improved fresh air supply in a cooking apparatus, an inner housing is provided to circumscribe a cooking chamber. A fan chamber is separated from the cooking chamber via at least one flow guide element. The fan chamber has a fan with a fan wheel which comprises primary blades on its side facing the first flow guide element and auxiliary blades on its side facing the wall of the inner housing through which the axle of the fan wheel passes to connect with a motor arranged outside of the inner housing. The fan wheel is provided for the circulation of cooking atmosphere and/or suction of fresh air into the inner housing via a fresh air channel, a mouth of which is separated from the axle of the fan wheel and runs into the inner housing through the wall. Fresh air sucked in through the fresh air channel is initially conducted via at least a second flow guide element which prevents a direct impingement of the fresh air on the auxiliary blades and prevents an angular momentum effect by the auxiliary blades from being imparted on the fresh air. The fresh air then is conducted from the axle of the fan wheel into the cooking chamber via the radial guiding or conveying effect of the auxiliary blades.

BACKGROUND

The method and apparatus concerns a method for improved fresh air supplyin a cooking apparatus and a cooking apparatus with an inner housingdefining a cooking chamber as well as a fan chamber (separated from thecooking chamber via at least one flow guide element) for a fan with afan wheel impeller which comprises primary blades on its side facing thefirst flow guide element and auxiliary blades on its side facing thewall (in particular back wall) of the inner housing through which theaxle of the fan wheel passes to connect with a motor arranged outside ofthe inner housing. The fan wheel is provided for the circulation ofcooking atmosphere and/or suction (intake) of fresh air into the innerhousing via a fresh air channel whose mouth runs into the inner housingthrough the aforesaid wall of the same separated from the axle of thefan wheel.

Such cooking apparatuses are known in the prior art, see for exampleEuropean Application 0 386 862 B1. They represent what are known ascirculation air cooking apparatuses that allow an at least temporaryfresh air supply to adjust desired climate proportions in the cookingchamber. For this purpose, fresh air is typically conveyed from akitchen atmosphere into a cooking chamber of the cooking apparatus inorder to displace portions of a cooking atmosphere, whereby the freshair fraction of the aforesaid cooking atmosphere is increased while thefraction of other components such as water vapor, carbon dioxide,aromatic compounds and food-specific outgases is reduced. In suchcirculation cooking apparatuses in which the cooking atmosphere issignificantly rotated via primary blades of a fan, a negative pressurefor the take-up of fresh air via a fresh air channel is forced usingauxiliary blades rotating with the primary blades and lying opposite thesame. However, due to the scarce space ratios in a cooking device, it issometimes not possible to place the mouth of the fresh air channel inthe inner chamber (comprising the. cooking chamber) of the cookingapparatus in axial proximity to the fan wheel where (in principle)optimal pressure ratios prevail. This has the disadvantage that now nomaximum negative pressure is available as a driving force for the intakeof the fresh air.

Furthermore, specified in DE 103 39 099.5 (not previously published) bythe applicant is a cooking apparatus that ensures an improved fresh airsupply in that the, so to speak, blind, mutually rotating air and/orcooking atmosphere is or are directed over at least one constriction onthe back side of a fan wheel, thus on the side opposite the primaryblades (which side is equipped with auxiliary blades) during eachrotation of the fan wheel, such that there a streamline compressionoccurs. This streamline compression is accompanied with a pressurereduction given nearly isochoric state changes.

SUMMARY

It is an object to further develop the method such that thedisadvantages of the prior art are overcome, and thus an improved freshair supply is present. A design simpler in terms of construction shouldbe provided that also enables a retrofitting of flow circulation cookingapparatuses.

A method is provided for improved fresh air supply in a cookingapparatus. An inner housing circumscribes a cooking chamber as well as afan chamber. The fan chamber is separated from the cooking chamber viaat least a first flow guide element. The fan chamber has a fan with afan wheel comprising primary blades on its side facing the first flowguide element and auxiliary blades on its side facing a wall of theinner housing through which an axle of the fan passes. The fan wheelprovides at least one of circulation of cooking atmosphere and suctionof fresh air to the inner housing via a fresh air channel, a mouth ofwhich runs into the inner housing through the inner housing wallseparated from the axle of the fan wheel. Fresh air is sucked in throughthe fresh air channel via at least a second flow guide element, whichprevents a direct impingement of the fresh air on the auxiliary bladesand/or prevents an angular momentum caused by the auxiliary blades frombeing impressed onto the fresh air. The fresh air is then guided fromthe axle of the fan wheel into the cooking chamber via a radial guideeffect of the auxiliary blades.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view through a cooking apparatus with fresh airsupply in a first embodiment;

FIG. 2 is a sectional view through a cooking apparatus with fresh airsupply in a second embodiment;

FIG. 3 is a sectional view through a cooking apparatus with fresh airsupply in a third embodiment; and

FIG. 4 is a perspective plan view of the back wall of a cookingapparatus showing second and third glow guide elements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the preferred embodimentsillustrated in the drawings and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the invention is thereby intended, such alterations andfurther modifications in the illustrated devices, and/or methods, andsuch further applications of the principles of the invention asillustrated therein being contemplated as would normally occur now or inthe future to one skilled in the art to which the invention relates.

With the disclosed method of the preferred embodiment, fresh air suckedin through the fresh air channel is initially conducted via at least asecond flow guide element preventing a direct impingement on theauxiliary blades while allowing a rotary guiding effect by the auxiliaryblades near the axle of the fan wheel. The air is then guided orconducted from the axle of the fan wheel into the cooking chamber viathe radial conduction effect of the auxiliary blades.

Thus a rotation of the fresh air in the region between the secondcurrent conductor element and the aforesaid wall is significantlyprevented via the use of at least one third flow guide element.

It is also provided that the current resistance for the fresh air uponentrance of the fresh air from the fresh air channel into the innerhousing in the region between the aforesaid wall and the second flowguide element is reduced in that the cross-section of the mouth of thefresh air channel is selected larger than the cross-section of the freshair channel.

The cooking apparatuses of the preferred embodiments are characterizedby at least a second flow guide conductor element that partitions theregion between the wall and the auxiliary blades into two interveningspaces at least in the region of the mouth of the fresh air channel, andleaves open the region of the axle of the fan wheel, whereby fresh aircan be guided or conducted from the fresh air channel via a firstintervening space, significantly without eddies near the axle, and fromthe area of the axle into the cooking chamber via the second interveningspace via auxiliary blades.

It can thereby be provided that the second flow guide elementsignificantly extends over the running area of the auxiliary blades andexhibits an opening for the passage of the axle of the fan wheel.

It is also provided with the preferred embodiment that the second flowguide element is aligned towards the axle of the fan wheel, inparticular runs essentially perpendicular to the same, are preferablyrotationally symmetrical to the same.

Preferred embodiments of the cooking chamber can be characterized by atleast a third flow guide element between the second flow guide elementand the aforesaid wall to prevent a rotation of the fresh air in thefirst intervening space, whereby the third flow guide element preferablystands essentially perpendicular to the second flow guide element and/orthe aforementioned wall.

A plurality of third flow guide elements can thereby be provided,whereby preferably each third flow guide element spreads outwardsradially from the axle of the fan wheel.

It also may be provided that the cross-section of the mouth of the freshair channel is larger than the cross-section of the fresh air channel,whereby the cross-section of the mouth is preferably adjustable via atleast one adjustment element.

It can be provided that a sealing element is arranged in the fresh airchannel, preferably in the form of an adjustable diaphragm or flap.

Embodiments are also provided that are characterized by at least onesensor to detect at least one climate parameter.

Furthermore, it can be provided that a first, second and/or third flowguide element is or are movable, in particular portable, deployable,guidable, rotatable, and/or pivotable.

Finally, with preferred embodiments, by a control and/or regulationdevice in effective connection with the fan (in particular the motor ofthe fan wheel), the first flow guide element, the second flow guideelement, the third flow guide element, the adjustment element, thesealing element and/or the sensor may be provided.

The preferred embodiment is based on the surprising realization that asupply of non-rotating fresh air in the region between the wall of aninner housing of a cooking device, in particular the back wall of theinner housing, and a fan wheel in the inner housing in direct proximityto the axle of the fan wheel itself, is possible when the mouth of afresh air channel in the inner housing is spaced away from the aforesaidaxle in order to use the entire length of auxiliary blades (that areprovided on the side of the fan wheel facing towards the back wall) toconvey the fresh air into the cooking chamber. For this purpose, theregion between the auxiliary blades and the back wall is divided (via aflow guide element that acts as a partition wall) into two interveningspaces that are only connected with one another via an opening in theaforesaid flow guide element near the axle of the fan wheel. Fresh airdrawn in via the fresh air channel can thus arrive in the region betweenthe back wall and the flow guide element (first intervening space) inorder to then flow via the opening of the flow guide element into theregion between the current conductor element and the auxiliary blades(second intervening space), the fresh air arriving into the cookingatmosphere and finally into the cooking chamber via the conveying effectof the auxiliary blades. Nearly the same pressure ratios that would bepresent in the case in which the mouth of a fresh air channel were tolie in immediate proximity of the axle of the fan wheel are thusrealized in the fresh air supply with a separation from the axle of thefan wheel.

In the structural embodiment of the mouth of the fresh air channel, bothcorresponding to the fresh air channel and the back wall of the innerhousing, substantially no eddies should form between the flow guideelement and the back wall that, due to their rotation, would oppose aninhibitive pressure of the fresh air supply in the first interveningspace. On the one hand, in the arrangement of the partition wall-likeflow guide element, care must be taken that the supplied fresh air isnot accelerated in the first intervening space. Thus a minimum distancebetween the back wall and the aforesaid flow guide element ismaintained. On the other hand, the flow guide element is to be separatedfrom the auxiliary blades such that the drawn-in fresh air in the secondintervening space is set in rotation to a degree that sets a desiredflow volume.

As is to be learned from FIG. 1, a cooking apparatus which acts as acirculation air cooking apparatus comprises an outer housing 2 in whichis arranged upon interposition of an insulation 3 an inner housing 4which, among other things, comprises a back wall 4 a. A cooking chamber5 and a fan chamber 6 that are separated from one another via a firstflow guide element 7 are in turn provided within the inner housing 4.Cooking atmosphere 8 can be circulated in the inner housing 4 via a fan9, while fresh air 11 can be introduced into the inner housing 4 via afresh air channel 10 given an open flap 12 in the region of a mouth 13.For this purpose, the fan 9 comprises a fan wheel 91 with primary blades(see primary blade edges 92) on its side facing the first currentconductor element 7, and thus the cooking chamber 5, and auxiliaryblades (see auxiliary blade edges 93) on its side facing away from thecooking chamber 5 and thus facing the back wall 4 a. The fan wheel 91can be driven by a motor 99 via an axle 98.

If, given an open flap 12, fresh air 11 is drawn in via the fresh airchannel 10 through the mouth 13 into the region between the back wall 4a and the auxiliary blades 93 (separated by the axle 98), a second flowguide element 100 provides that the fresh air 11 does not directlyimpinge on the auxiliary blades 93, but rather initially is guided orconveyed within a first intervening space 110 a into the proximity ofthe axle 98 in order to there be conveyed into the cooking chamber 5 viathe conveying force of the auxiliary blades 93 via passage of a secondintervening space 110 b. Both intervening spaces 110 a, 110 b are thusprovided via the inter-arrangement of the flow guide element 100 betweenthe back wall 4 b and the auxiliary blades 93, whereby a connection ofboth intervening spaces 110 a and 110 b is ensured by an opening 101 inthe second flow guide element 100 in the region of the axle 98.

The path of the flow of the fresh air 11, 11′, 11″ via use of the secondflow guide element 100 is shown in FIG. 2. According to that Figure, thefresh air 11 is guided or conveyed (substantially without eddies)through the fresh air channel 10 and into the first intervening space110 a, while in the region of the opening 101 of the second flow guideelement 100 there is a rotary effect caused by the auxiliary blades 93,so that the fresh air then placed into rotation for transport into thecooking chamber flows through the second intervening space 110 b, intothe cooking chamber as shown at 11″.

It can be learned from FIG. 2 that the back wall 4 a runs displacedoutwardly in the region of the fan wheel 91 to enlarge the interveningspaces 110 a, 110 b between the auxiliary blades 93 and the back wall 4a.

The cooking apparatus of FIG. 3 differs from that of FIG. 2 inasmuch asthe mouth 13′ of the fresh air channel 10 in the inner housing 4exhibits a cross-section that is larger than the cross-section of thefresh air channel 10 itself. This provides for a reduction of thecurrent resistance of the fresh air 11 upon entrance of the same intothe first intervening space 110 a.

In FIG. 4, a cooking apparatus is shown that, to further prevent arotation of the fresh air 11 in the first intervening space 110 a,comprises third flow guide elements 120 in the form of a plurality ofribs radially extending away from the axle 98 of the fan wheel 91. Theflow of the fresh air 11′″ runs between the ribs towards the axle 98substantially without eddies.

While preferred embodiments have been illustrated and described indetail in the drawings and foregoing description, the same is to beconsidered as illustrative and not restrictive in character, it beingunderstood that only the preferred embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the invention both now or in the future are desired to beprotected.

1. A method for improved fresh air supply in a cooking apparatus,comprising the steps of: providing an inner housing to circumscribe acooking chamber as well as a fan chamber, the fan chamber beingseparated from the cooking chamber via at least a first flow guideelement, the fan chamber having a fan with a fan wheel which comprisesprimary blades on its side facing the first flow guide element andauxiliary blades on its side facing a wall of the inner housing throughwhich an axle of the fan wheel passes to connect with a motor arrangedoutside of the inner housing; providing said fan wheel for at least oneof circulation of cooking atmosphere and suction of fresh air into theinner housing via a fresh air channel whose mouth runs into the innerhousing through said inner housing wall separated from the axle of thefan wheel; guiding fresh air, sucked in through the fresh air channel,near the axle of the fan wheel by at least one second flow guide elementwhich at least one of prevents a direct impingement of the fresh air onthe auxiliary blades and prevents an angular momentum caused by theauxiliary blades from being impressed onto the fresh air; and guidingthe fresh air from the axle of the fan wheel into the cooking chamber bya radial conveying effect of the auxiliary blades.
 2. A method accordingto claim 1 wherein a rotation of the fresh air in a region between thesecond flow guide element and said wall is significantly prevented viause of at least one third flow guide element.
 3. A method according toclaim 1 wherein a flow resistance for the fresh air is reduced uponentrance of the fresh air from the fresh air channel into the innerhousing in the region between said wall and the second flow guideelement such that a cross-section of the mouth of the fresh air channelis selected larger than a cross-section of the fresh air channel.
 4. Acooking apparatus, comprising: an inner housing to circumscribe acooking chamber as well as a fan chamber for a fan, the fan chamberbeing separated from the cooking chamber via at least one flow guideelement; the fan comprising a fan wheel which comprises primary bladeson its side facing the first flow guide element and auxiliary blades onits side facing a wall of an inner housing through which an axle of thefan wheel passes to connect with a motor arranged outside of the innerhousing; said fan wheel being designed for at least one of circulationof cooking atmosphere and suction of fresh air into the inner housingvia a fresh air channel, a mouth of the channel being separated from thefan wheel axle which runs into the inner housing through said wall; andat least one second flow guide element that partitions a region betweenthe wall and the auxiliary blades into first and second interveningspaces at least in a region of the mouth of the fresh air channel, andleaves open a region of the axle of the fan wheel so that fresh air isguided from the fresh air channel via a first intervening spacesubstantially without eddies to a region near the axle, and from theregion near the axle into the cooking chamber via the second interveningspace via said auxiliary blades.
 5. A cooking apparatus according toclaim 4 wherein the second flow guide element substantially extends overa movement region of the auxiliary blades and exhibits an opening forpassage of the axle of the fan wheel.
 6. A cooking apparatus accordingto claim 4 wherein the second flow guide element is aligned towards theaxle of the fan wheel, is running substantially perpendicular to theaxle, and is rotatably symmetrical to the axle.
 7. A cooking apparatusaccording to claim 4 wherein at least a third flow guide element isprovided between the second flow guide element and said wall to preventa rotation of the fresh air in the first intervening space, the thirdflow guide element being substantially perpendicular to at least one ofthe second flow guide element and said wall.
 8. A cooking apparatusaccording to claim 7 wherein a plurality of third flow guide elementsare provided, each third flow guide element extending radially outwardlyfrom the axle of the fan wheel.
 9. A cooking apparatus according toclaim 4 wherein a cross-section of the mouth of the fresh air channel islarger than a cross-section of the fresh air channel, the cross-sectionof the mouth being adjustable by at least one adjustment element.
 10. Acooking apparatus according to claim 4 wherein a sealing element isprovided in the fresh air channel which is in a form of at least one ofan adjustable diaphragm and an adjustable flap.
 11. A cooking apparatusaccording to claim 4 wherein at least one sensor is provided to detectat least one climate parameter.
 12. A cooking apparatus according toclaim 4 wherein at least one of the first, second, and a third flowguide element is at least one of movable, portable, collidable,deployable, rotatable, and pivotable.
 13. A cooking apparatus accordingto claim 4 wherein at least one of a control and a regulation device isin effective connection with at least one of the first flow guideelement, the motor of the fan wheel, the second flow guide element, athird flow guide element, an adjustment element, a sealing element, anda sensor.
 14. A method for improved fresh air supply in a cookingapparatus, comprising the steps of: providing a housing to circumscribea cooking chamber as well as a fan chamber, the fan chamber beingseparated from the cooking chamber via at least a first flow guideelement, the fan chamber having a fan with a fan wheel which comprisesprimary blades on its side facing the first flow guide element andauxiliary blades on its side facing a wall of the housing through whichan axle of the fan wheel passes; providing said fan wheel forcirculation of cooking atmosphere and suction of fresh air into theinner housing via a fresh air channel whose mouth runs into the housingthrough said housing wall separated from the axle of the fan wheel;guiding fresh air, sucked in through the fresh air channel, near theaxle of the fan wheel by at least one second flow guide element whichprevents a direct impingement of the fresh air on the auxiliary bladesand prevents an angular momentum caused by the auxiliary blades frombeing impressed onto the fresh air; and guiding the fresh air from theaxle of the fan wheel into the cooking chamber by a radial conveyingeffect of the auxiliary blades.
 15. A cooking apparatus, comprising: ahousing to circumscribe a cooking chamber as well as a fan chamber for afan, the fan chamber being separated from the cooking chamber via atleast one flow guide element; the fan comprising a fan wheel whichcomprises primary blades on its side facing the first flow guide elementand auxiliary blades on its side facing a wall of a housing throughwhich an axle of the fan wheel passes; said fan wheel being designed forcirculation of cooking atmosphere and suction of fresh air into theinner housing via a fresh air channel, a mouth of the channel beingseparated from the fan wheel axle which runs into the housing throughsaid wall; and at least one second flow guide element that partitions aregion between the wall and the auxiliary blades into first and secondintervening spaces at least in a region of the mouth of the fresh airchannel, and leaves open a region of the axle of the fan wheel so thatfresh air is guided from the fresh air channel via a first interveningspace substantially without eddies to a region near the axle, and fromthe region near the axle into the cooking chamber via the secondintervening space via said auxiliary blades.